Chlorine Dioxide Decontamination System and Methods

ABSTRACT

A scalable, portable and modular chlorine dioxide fumigant decontamination system having an activating area and a neutralizing area which may be housed separately or as a single operationally connected unit, and which may be configured as a closed loop system connected to a decontamination chamber for decontamination of articles, or as an open loop system for decontamination of interiors and large confined spaces, and employing a specialized activating cup that is permeable to air yet substantially impermeable to water and chlorine dioxide reaction by-products such that directing air through the activation cup releases nearly pure chlorine dioxide fumigant. Methods and articles relating to the system are also described.

PRIORITY

This application claims priority under 35 U.S.C. §119(3) to U.S.Provisional No. 62/042,398, filed Aug. 27, 2015, the entire disclosureof which is incorporated herein by this reference.

TECHNICAL FIELD

The subject matter of this application relates generally to the chemicaldecontamination arts and more specifically to chlorine-dioxide fumigantbased decontamination systems and methods.

BACKGROUND

Chlorine dioxide (CD or ClO₂) was discovered in the early 1800's, andhas been approved for a wide variety of commercialdisinfecting/sterilizing applications by the EPA, FDA and USDA. Due toits demonstrated efficacy with respect to a wide variety of contaminatedsurfaces, ClO₂ has been called the ideal biocide and the ability ofchlorine dioxide to reduce or eliminate microbes, e.g., bacteria,viruses, fungi, mold spores, algae and protozoa, at relatively lowconcentrations is well-documented. Because ClO₂ inactivatesmicroorganisms by oxidizing critical components of a microorganism'smembrane proteins, tolerance to ClO₂ does not develop, making it anideal disinfectant/sterilant for repeated-use applications such as in ahospital environment.

ClO₂ is a green-yellowish gas with a chlorine-like odor; however ClO₂ isa neutral chlorine compound. ClO₂ is a small, volatile and very strongmolecule. In diluted, watery solutions ClO₂ is a free radical. At highconcentrations it reacts strongly with reducing agents. Chlorine dioxideis an unstable gas that dissociates into chlorine gas and oxygen gasreadily. Further, ClO₂ may be photo-oxidized by sunlight and thereforedecontamination applications generally proceed in the absence of light.The end-products of ClO₂ neutralization/degradation reactions arechloride (Cl—), chlorite (ClO—) and chlorate (ClO3-).

ClO₂ is not as reactive as ozone or chlorine and it generally reactsonly with sulphuric substances, amines and some other reactive organicsubstances. In comparison to chlorine and ozone, less chlorine dioxideis required to obtain an active residual disinfectant. It can also beused when a large amount of organic matter is present in theenvironment.

A significant drawback of ClO₂ is that it is explosive under pressure,thus making it difficult to transport. It cannot be transported inliquid phase or under pressure; hence it is typically manufactured onsite (in situ). ClO₂ is usually produced as a watery solution or gas. Itis produced in acidic solutions of sodium chlorite (NaClO₂), or sodiumchlorate (NaClO₃). Sodium chlorite, chlorine gas (Cl₂), sodium hydrogenchlorite (NaHClO₂) and sulphuric or hydrogen acid are typically used forthe production of chlorine dioxide on site. In the presence of sunlight,ClO₂ in air will decompose to chlorine and oxygen. The chlorine willreact with any moisture in the air to form a hydrochloric acid mist. Ifthe concentration of ClO₂ in air in a confined space is above 10%, thechlorine dioxide is at an explosive concentration and can be ignited byalmost any form of energy such as sunlight, heat or sparks, includingfor example, static electrical energy. Concentrations above 40% willgenerate a decomposition/shock wave if set off by any ignition source.

Other decontamination systems which exploit the beneficial properties ofClO₂ fumigant are known in the art. However, these systems generallysuffer from production of excess humidity with the fumigant, resultingin production of hydrochloric acid mist and potential to corrodeelectronic equipment, making the system inconvenient for large-scalebuilding decontamination, since removal of corrosion-sensitive articlesmust be effectuated prior to decontamination. Further, even whencorrosion-sensitive articles are removed from the area, metallicstructural components of buildings may be affected. In addition to thecorrosive effects of moisture, salts existing as by-products of ClO₂generation reactions and often present in the fumigant, are known tocause damage to structures and articles undergoing decontamination. Thisis particular problematic to areas that must be repeatedly disinfected,such as in the medical/hospital context, since the damaging effectsaccrue.

U.S. Pat. No. 8,524,167 (the '167 patent) discloses a ClO₂decontamination system, however it suffers from failure to providemechanisms for removal of byproducts and relies on humidification as anecessary aspect of effective ClO₂ fumigant decontamination, going sofar as to add a humidifier to a decontamination chamber. The '167 patentsystem is unsuitable for corrosion-sensitive articles and environments.A critical consideration is that that the registered concentration ofClO₂ cannot be trusted, since chlorine gas is known to influence thesensors toward detection of chlorine dioxide and to result inartificially high concentration read-outs. Chlorine gas is produced as aresult of the humidification. Further, the '167 fumigant scrubber reliesheavily on carbon, which is rendered less effective by the presence ofwater. Notably, the use of carbon filtration with non-degraded ClO₂ cancreate an explosive potential because ClO₂ can build up in the carbonpores in problematic concentrations. Hence, the use of carbon as aprimary neutralizer/scrubber presents a significant fire and safetyhazard.

Known ClO₂ fumigant systems generally utilize a reaction sachet (bag)for generation of the gas with water, and sparging of the gas productfrom the liquid. The result is that acid vapor and chlorine gas areoften present in the CD fumigant. As noted, both of these gases arehighly corrosive to metals, and chlorine, in particular, is incompatiblewith many non-metallic substances as well. Neutralization of thefumigant is complicated by the presence of these additional toxic gases.Prolonged treatment time results where multiple passes are required forneutralization.

In a highly publicized recent decontamination effort by the U.S.government, a ClO₂ fumigant system was employed to decontaminate abuilding contaminated with Anthrax spores that were released from aletter opened in a mail room. The building was tented prior tofumigation and sparged ClO₂ gas was pumped into the building's heating,ventilating and air conditioning (HVAC) system to achieve a targetconcentration of 500 ppm at 75° F. and 75% relative humidity for 18hours. Biological indicators (BI) comprising standard b. subtilus sporestrips were placed throughout the facility. (Standard BIs contain 106natural pathogens—sufficient to indicate a maximum 6-log sporereduction, however the BI's were not normed to Anthrax). Hence theeffectiveness of decontamination was also tested via swipe sampling.Reportedly, the original plan to neutralize the ClO₂ with ascorbic acidwas abandoned when very high concentrations of chlorine gas were foundlocalized throughout the building. Because the presence of chlorinemolecules interferes with ClO₂ monitoring to yield false highconcentration readings, it was presumed therefore that concentrationtargets were not actually met and the procedure had to be repeated threetimes over 9 months for a total cost of nearly 50 million dollars toU.S. taxpayers.

Clearly there remains a need in the art for safe and effective ClO₂fumigant decontamination systems that minimize use of water, minimizeagitation/degradation of the CD fumigant, and that avoid dispersal ofwater vapor, acid and chlorine gas along with the fumigant.

SUMMARY

Accordingly, the present investigators have developed a ClO₂ fumigantdecontamination system that overcomes these and other deficiencies inthe art. In particular, the disclosed system provides a ClO₂ fumigantthat is substantially free of water vapor, acid vapors and otherby-products of ClO₂ gas production. Thus, the ClO₂ decontaminationsystem may be utilized in a broad range of applications, including forexample, sterilization of corrosion-sensitive electronic equipment andmetallic substrates, sterilization of environments for human habitation,and sterilization of operating rooms, medical devices, and otherenvironments/devices that may be subject to repeated sterilization.Further, the ClO₂ fumigant decontamination system provides an aspect ofone-pass neutralization, simplifying and decreasing the expense and timeassociated with large-scale decontamination projects generally. Thesystem is modular and portable, offering not only increased convenience,but the operational capacity to locate additional ClO2 fumigantactivating areas throughout a large area to be decontaminated dependenton target concentrations and area to be decontaminated.

One embodiment of the invention provides decontamination systemscomprising: a chlorine dioxide (ClO₂) fumigant activating area,optionally, a by-pass flow area, a neutralizing area; a first airblower, preferably having variable speed and in direct fluidcommunication with the ClO₂ fumigant activating area, the by-pass flowarea and the neutralizing area; and a valve system for dedicating airflow from the blower to one or more of the areas. The activating areacomprises a novel activation cup configured to receive reagents for thein situ generation of ClO₂ fumigant. The activation cup is fabricated tobe permeable to air and substantially impermeable to water and reactionby-products. The activation cup may be attached to a plate and suspendedin the activation area such that air flowing from the first variablespeed air blower into the activation area flows through and around theactivation cup such that generated ClO₂ fumigant passes out of theactivation cup with the air flow, while water and reaction by-productsremain in the activation cup. Thus, ClO₂ fumigant produced according tothe inventive decontamination system is substantially free of watervapor, acid vapor and chlorine gas.

Other embodiments provide methods for generating chlorine dioxidefumigant in a directed flow with a minimum of water. The methodscomprise (a) providing an activation cup comprising: an outer layer ofcrush-resistant thermally bondable non-woven fibers molded into atransversely bisected aerodynamically-shaped shell, said shell open atthe top and having an interior surface and an exterior surface, saidexterior surface and interior surface comprising a pattern ofcorrugations; at least one filter layer including one filter layeradjacent and adherent to an inner surface of the outer layer, wherein atleast one filter layer comprises high-loft electret chargedfluorine-coated polyolefin microfibers, wherein the activation cup isadapted to retain water and reaction by-products while permitting gas topass through; (b) flexibly suspending the activation cup; (c) adding dryreagents for production of ClO₂ fumigant to the cup; (d) directing anair flow toward the cup at a low speed such that the corrugations createturbulence resulting in vibration of the cup and acceleration of ClO₂generation, “low” being defined as insufficient to degrade ClO₂; (e)adding water to the cup; thereby initiating generation of ClO₂ fumigantthat is directed out of the cup with the air flow while water and ClO₂generation reaction by-products are substantially retained in the cup.

Further embodiments provide methods for neutralizing chlorine dioxide(ClO₂) fumigant in a sealed neutralizing area, said neutralizing areacomprising a leak abatement space and a neutralizing space, saidneutralizing space comprising a series of treatment stations and atleast one blower, the method comprising: (a) blowing ClO₂ fumigantto-be-neutralized into a treatment station comprising ultraviolet light,resulting in partially neutralized air, said blowing effectuated at aspeed high enough to degrade ClO₂; (b) blowing the partially neutralizedair from the UV treatment station through a diffusion plate and into atreatment station comprising a neutralizing solution reservoir, therebycreating bubbling and frothing in the reservoir and resulting insubstantially neutralized air; (c) capturing and returning solution tothe reservoir with a treatment station comprising a humidificationfilter that permits the substantially neutralized air to pass throughthe filter and into a treatment area comprising coated zeolite; (d)passing the substantially neutralized air through the coated zeolite toneutralize any remaining ClO₂ and other toxic gaseous by-productsremaining, resulting in neutralized air; and, (e) optionally, passingthe neutralized air through activated carbon to remove odiferousmolecules which may be present in the neutralized air.

Embodiments directed to a fumigant activation cup are also disclosed.The cup comprises (a) an outer layer of crush-resistant thermallybondable non-woven fiber molded into a transversely bisectedaerodynamically-shaped shell, said shell open at the top and having aninterior surface and exterior surface; (b) at least one filter layer,including one filter layer adherent and adjacent to an inner surface ofthe outer molded layer; (c) an inner layer of crush-resistant fibrousmaterial adjacent and adherent to the at least one filter layer; whereinthe at least one filter layer comprises high-loft electrically chargedfluorinated polyolefin microfibers and exhibits a higher melting pointthat the molded layers.

These and additional embodiments and aspects of the invention will beclarified by reference to the accompanying figures and detaileddescription, below.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts a cross-sectional schematic view of an exemplary combinedactivating area, bypass area, and neutralizing area; all operationallyconnected and contained in a single cabinet.

FIG. 2A shows an illustrative cup with a saddle-shaped horizontalcross-sectional shape; FIG. 2B shows a schematic cross-section of athickness of an edge of the cup illustrating a filter layer disposedbetween two molded layers; FIG. 2C illustrates several shapes suitableas the aerodynamic horizontal cross-sectional shape of the top perimeterof an activating cup.

FIG. 3 sets forth an exemplary schematic representation (not scaled) ofa closed loop system including activating and neutralizing areas whichmay or may not be combined into a single contained unit, operationallyconnected to a decontamination chamber.

FIG. 4 sets forth a schematic representation of decontamination of amultiple-floored building where decontamination is via the HVAC systemof the building and multiple additional portable activating areas arelocated on each of the floors over the HVAC unit location, all incommunication with the main decontamination unit.

FIG. 5A is the top view of the operating room showing a fumigant airflow into a high-efficiency particulate arrestance (HEPA)filter/diffuser positioned centrally over the operating table and intoslotted diffusers placed at either side of the operating area in orderto create an air curtain around the operating area; FIG. 5B shows aschematic representation of the operational combination of thedecontamination system with the operating room via the HVAC system; FIG.5C illustrates generation of ClO₂ fumigant and flow into the air supplyduct via an access port and then over the operating room via the HVACsystem; FIG. 5D shows the fumigant diffused into the operating room andcontained within the air curtain; FIG. 5E shows the fumigant directedinto the decontamination system where it may be neutralized orre-circulated depending on valve manipulation and need.

DETAILED DESCRIPTION

When describing embodiments of the system of the invention, the termdecontamination may be used to refer to all levels of sanitizing,sterilizing, disinfecting and deodorizing. Decontamination is a termused broadly to describe a process or treatment that renders a medicaldevice, instrument, surface, content, or environmental surface safe forhumans. Decontamination includes sterilization and disinfection.Disinfection eliminates virtually all pathogenic non-spore-formingmicroorganisms but not necessarily all microbial forms on inanimateobjects (work surfaces, equipment, etc.). Effectiveness is influenced bythe kinds and numbers of organisms, the amount of organic matter, theobject to be disinfected and chemical exposure time, temperature andconcentration. The CDC recognizes three levels of disinfection: (1)High-level Disinfection: A procedure that kills all organisms with theexception of bacterial spores and certain species, such as theCreutzfeldt-Jakob prion. Most high-level disinfectants can producesterilization with sufficient contact time. (2) Intermediate-levelDisinfection: A procedure that kills vegetative bacteria, includingacid-fast Mycobacterium tuberculosis, most fungi, and viruses but notbacterial spores. (3) Low-level Disinfection: A procedure that killsmost vegetative bacteria (but not M tuberculosis), some fungi, andviruses but no spores. Sterilization is destruction all microbial life,including highly resistant bacterial endospores.

The novel ClO₂ decontamination system as described herein generates ClO₂in a specialized activation area contained in a sealed portable cabinetusing directed air flow to provide target residential concentrations ofClO₂ to any desired area for the purpose of decontamination,disinfecting, sterilization, and deodorization. The system componentsoperate in synchrony to achieve safe and highly efficient production ofsubstantially pure ClO₂ fumigant. “Substantially pure” ClO₂ as usedherein is defined as a gas that is between 90 and 99.9% ClO₂ by weight,or between 95 and 99.9% ClO₂ by weight, or between 98 and 99.5% ClO₂ byweight, or over 99% ClO₂ by weight. The system is versatile in that itcan be configured and scaled for small, large and complex configurationsand environmental applications. Components of the system may beseparated and used independently or in multiples, depending on thedecontamination environment and needs.

Embodiments and aspects of the invention will be described withreference to the Figures, which are intended to be illustrative and notlimiting of the scope of the invention as defined by the claims.

FIG. 1 sets forth an exemplary aspect of a decontamination system 1: achlorine dioxide (ClO₂) fumigant activating area 3, a by-pass flow area5, and a neutralizing area 7. A first variable speed air blower 9 is indirect fluid communication with the ClO₂ fumigant activating area 3, theby-pass flow area 5 and the neutralizing area 7. As illustrated, theactivating, bypass and neutralizing areas may be housed in a singlesealed container or “cabinet.” Variable speed is advantageous in orderto adapt the flow speed to particular decontamination needs andenvironmental sizes and configurations. Further, where the blower isdirected to the activating area relatively low flow force may bedesirable in order to avoid degrading the ClO₂ and producing chlorinegas; whereas when flow is directed to the neutralizing area higherspeeds may be desired in order to promote degradation of the ClO₂. Thesystem further comprises a valve system 11 for dedicating air flow fromthe blower 9 to one or more of the areas 3,5,7.

The activating area 3 comprises an activation cup 13 configured toreceive reagents for in situ generation of ClO₂ fumigant. The activationcup 13 is permeable to air; yet substantially impermeable to water andreaction by-products. The activation cup is flexibly suspended in theactivation area 3 such that air flowing from the first variable speedair blower 9 into the activation area flows through and around theactivation cup such that generated ClO₂ fumigant 15 passes out of theactivation cup 13 with the air flow while water and reaction by-productsremain in the activation cup 13.

Referring now to FIG. 2, according to certain embodiments the activationcup 13 comprises: an outer layer 15 of crush-resistant thermallybondable non-woven fiber molded into a transversely bisectedaerodynamically-shaped shell 17. The shell 17 is oriented in theactivating area such that it is open at the top 19. As illustrated inFIG. 2B, the shell has an interior surface 21 and an exterior surface 23and at least one filter layer 15 interposed between the two moldedlayers. The filter layer includes one filter layer adjacent and adherentto an inner surface 16 of the outer molded layer 15. The cup has aninner layer 27 of crush-resistant fibrous material adjacent and adherentto the at least one filter layer 25. The at least one filter layer 25 isfabricated from a high-loft electrically charged polymeric microfibers.“High-loft” is understood in the art to mean a fiber structure thatcontains more air then fiber. In more specific embodiments, thepolymeric microfibers comprise electrat charged fluorinated melt-blownpolyolefin microfibers having an effective fiber diameter of betweenabout 0.5 μm and 12 μm, or more specifically between about 0.7 μm and 8μm, or even more specifically having an average effective fiber diameterof about 1 μm. In particular embodiments, the air permeability of thefiber layer is between 80 l/m²/s and 8000 l/m²/s, and according tospecific embodiments is between 100 l/m²/s and 1000 l/m²/s. Air flowresistance according to some embodiments is between 1.5 Pa and 100 Pa.Fibrous filter media suitable for embodiments of the invention areavailable from Hollingsworth & Vose of East Walpole, Mass.

As shown in FIG. 2C, according to some embodiments the shell has agenerally aerodynamic shape as defined from the front to the rear, thefront being the leading edge of the air flow. Nearly any shape resultingin a substantially laminar flow of air around the contour of the shellis suitable. Non-limiting examples of suitable shapes of the horizontalcross-section of the shell include a substantially triangular shape 29,a teardrop shape 31, a pear shape 33, an aerofoil shape, or a saddleshape 35. In a very specific embodiment, the shape is saddle-shaped.

According to some embodiments, the exterior surface 23, or both theexterior surface 23 and the interior surfaces 21, of the shell 17include a pattern of corrugations 37 effective to create turbulence inthe airflow around and through the cup 13 resulting in vibration of thecup 13 and accelerated activation of ClO₂ fumigant. Any pattern ofsurface features is suitable; however generally the patterning should besymmetric about a horizontal axis lengthwise through the shell in orderto avoid excessive agitation.

The activation area 3 comprises a series of conduits for addition ofwater, reagents and neutralizing solution to either the activation cupor directly into the air flow. The conduits include a first conduit 4adapted for controlled metered addition of water to the activation cup13, a second conduit 6 adapted for addition of dry reagents to theactivation cup 13, and a third conduit 8 adapted for addition ofneutralizing reagents to the activation cup. Any commercially availabledry reagents for the production of ClO₂ are suitable. In specificembodiments, the dry reagents are added as a tablet, for example, atablet comprising sodium chlorite and sodium Dichloroisocyanuratedihydrate. Inorganic acids and inorganic salts may also be included.Suitable dry-reagent tablets activated to produce ClO₂ upon addition ofwater are available from Quip Laboratories, Inc. of Wilmington, Del.

The conduits 4 6 8 may be controlled by ball-valves 10 which may beopened and closed by manual turning, or by automated turning achievedwithout manual touching. In some embodiments, the by-pass area 5comprises at least one conduit 8 in communication with a pipe or tubetraversing the by-pass area 5 for addition of neutralizing reagentsdirectly to the air flow.

The neutralizing area 7 comprises two distinct functional spaces—a leakabatement space 39 and a ClO₂ fumigant neutralization space 41. Althoughthe neutralizing space will be described as a series of treatmentcenters in sequential order, it is understood that any additionaltreatment stations may be included at any point as determined byparticular needs. Air flow may be directed into the neutralizing spaceby valve manipulation. The ClO₂ fumigant neutralizing space 41comprises: a first treatment station 43 comprising ultraviolet light(UV). According to specific embodiments, the inside of the UV treatmentcenter includes a UV light source and a reflective interior surface toincrease exposure of the ClO₂ gas to the UV light in the station. The UVtreatment station is contained within a compartment that may beirregularly shaped to further increase disruption in the ClO₂ air flow,which results in increased dwell/residential time in the UV station. Insome embodiments, the variable speed blower is positioned to directfumigant air flow to a wall of the UV compartment, further creatingdisruption in the flow and UV exposure dwell time. The user is protectedfrom exposure to the UV light since the system is contained within asealed opaque container, such as a cabinet. In very specific embodimentsthe UV light is designed to turn off when the cabinet is opened.

The first treatment station 43 is in operational communication with avariable air blower 45. Generally, when the activating area andneutralizing area are housed together, a single variable air blower withdedication capability comprising, for example, flow valves, may beutilized, although this is not always necessary. In embodiments wherethe activating area and neutralizing area are contained separately,different variable air blowers may be employed for the activating versusneutralizing functionality. It is clear that various configurations ofair blowers may be utilized without departing from the spirit of theinvention. In comparison to the relatively low flow force generated bythe air blower for activation functionality, the air blower 45 is set toblow fumigant waste air at a relatively high speed through the firsttreatment station. “High” in this context is defined as at a forcesufficient to agitate and degrade ClO₂ present in the fumigant wasteair, thereby resulting in partially treated air. The air flow from thevariable air blower 45 is directed to an interior surface of the UVstation compartment in order to create flow disturbances as the air flowpasses into the second treatment area. Partially treated air may includeboth ClO2 and degradation products of ClO₂.

Upon exiting the first treatment center, the now-disrupted air flowenters a second treatment station 47 comprising a reservoir 49 of liquidneutralizing solution. ClO₂ neutralizing solutions are known in the art.According to a preferred embodiment, the neutralizing solution comprisessodium thiosulfate and water. In some embodiments a diffusion plate 51or baffle separates the first and second treatment stations. As thedisrupted flow is forced into the neutralizing solution reservoir 49,frothing and bubbling and formation of turbulent flow features such aseddies occurs, further aiding the neutralizing process effectuated bythe neutralizing solution, both by the agitation and the extendedresidential time in the reservoir that results. In some embodiments thereservoir 49 is separated into at least three chambers. Diffusion platesor baffles may be utilized to separate/create the chambers, however allchambers contain the neutralizing solution reservoir. The secondchamber, which in preferred embodiments is also the largest chamber, isthe chamber from which the air flow enters the third treatment center.The second chamber is positioned between the first and third chambers.The first chamber is in direct communication with the first treatmentcenter and the flow passes into the first chamber at an angle, causingdisruptions in the flow. The third chamber on the opposite side of thesecond chamber from the first chamber is positioned to receive air flowfrom the leak abatement space powered by another blower functioning as are-circulating blower. A person of ordinary skill in the art willrealize that additional configurations of chambers designed to promoteturbulence and thereby increase the rate of the neutralizing reaction inthe reservoir may utilized. Generally, more chambers results in greaterturbulence and reaction mechanics favoring enhanced neutralization.

The waste fumigant air leaves the second treatment center 47 assubstantially treated air. As used herein, “substantially treated” meansthat only residual amounts of ClO₂ may remain in the air flow. Thesolution in the reservoir is bubbling and frothing from the flowdisruptions and forced flow through diffusion plates into the reservoir.The second treatment station is in communication with a third treatmentstation 53 comprising a humidification filter 55 positioned over thereservoir 49. The humidification filter 55 is configured to capture,contain and return neutralizing solution to the reservoir whilepermitting substantially treated air to pass through. In specificembodiments the humidification filter 55 is fabricated from open-celledpolymeric material. Localized high concentrations of neutralizing liquidmay form in some of the cells, further providing enhanced neutralizationcapacity. According to specific embodiments, the humidification filter55 comprises a humidification pad 60 and humidification fins 62. Insnore specific embodiments the humidification fins 62 comprise grooves64. Generally the fans are aligned above the reservoir 49 and beneaththe humidification pad 60.

As the air flow passes through the third treatment station it enters afourth treatment station 56 comprising coated zeolite 58. The zeolite 58may be coated with sodium thiosulfate or another suitable ClO₂ degradantor neutralizer. Specific organic materials are known in the art aseffective coatings for neutralization of ClO₂. In other specificembodiments calcium hydroxide may be coated over the zeolite to removecarbon dioxide.

In some embodiments a treatment station 57 comprising activated charcoalsuitable for removing odiferous molecules from the treated air may beincluded. For example, sulfur gas may be present in the treated air. Theactivated charcoal may be sprinkled into the zeolite or may form a layerover the zeolite, or may in some aspects be a layer distinct from thezeolite. It is an important consideration to the design of theneutralizing area that the waste fumigant is not contacted with acarbon-based filter until after the ClO₂ has been neutralized so as toavoid a fire hazard resulting from localized ClO₂ concentration build upin the spaces and pores of carbon filtration media.

According to some embodiments, the leak abatement space 39 comprises: ablower 59 adapted for pulling treated air through an exit port 61 of theneutralizing space 41 and into the leak abatement space 39. This bloweracts as a pull-blower and also aids in creating circulation of air inthe leak abatement space to ensure that any leaks into the internalspace of the cabinet are dispersed and re-circulated into theneutralizing space. A fifth treatment station 61 comprising UV light islocated in the leak abatement space. A second variable air blower 63 ispositioned to blow air from the leak abatement space 39 through thefifth treatment station 61 and into a chamber of the reservoir 49 at ahigh speed. In some embodiments, the air flow from the fifth treatmentstation is disrupted by directing the air flow from the blower 63 at anoblique angle to a containment wall of the UV treatment space such thatit enters the chamber of the reservoir as a disrupted air flow, creatingturbulence and eddy formation in the reservoir. A second diffusion plate65 or baffle may be positioned at an interface 67 between the fifthtreatment center 61 and the reservoir 49 to create bubbling and frothingin the reservoir. As used herein, “high” flow rate is defined assufficient to agitate and degrade ClO₂ present in the leak abatementspace 39.

In some embodiments the leak abatement 39 space may be connected to anenvironment external 71 to the sealed housing by one or more hoses 69including at least one hose connected to the variable speed blower 63 toprovide a vacuum force effective to pull potentially contaminated airfrom the external environment 71 and direct it into the fifth treatmentstation 61. A user may immediately decontaminate the externalenvironment where a leak is indicated by one or more sensors located inthe external environment by utilizing the vacuum hose. The air blowersof the system are sealed and configured to operate on direct-currentpower for safety. Ventilation blowers designed for marine (boating) useare suitable as the blowers of the decontamination system because theyare sealed to the immediate environment and water/moisture resistant.Such blowers are available from a number of suppliers including AttwoodMarine Products, Inc.

According to some embodiments the activating area 3 and neutralizingarea 7 may be housed together in one sealed housing 14, for example in acabinet. In other embodiments the areas may be housed separately inindependent sealed housings 16. In particular embodiments suited fordecontamination of buildings via the HVAC system, multiple independentlyhoused activating areas 3 may be employed throughout the building alongwith at least one neutralizing area 7, The cabinets, whether housingindependent activating or neutralizing areas or combinations thereof,may include wheels for simple portability, or other portability means(handles, pull handles and the like). In this way the decontaminationsystem may be configured as a modular and portable system. Further,systems may be converted readily from closed to open systems bymanipulation of sealed valves placed within the system piping.

According to some embodiments, the activation area 3 and neutralizingarea 7 are housed together in one sealed housing 14 and the systemfurther comprises a decontamination chamber 77. The sealed housingcomprises a ClO₂ fumigant outlet port 73 and a ClO₂ waste air inlet port75. The decontamination chamber 77 is scalable and configured to hold aproduct 79 to be decontaminated and comprising an inlet port 81sealingly connected by a positive flow line to the ClO₂ fumigant outletport 73 and an outlet port 84 sealingly connected by a negative flowline to the ClO₂ waste air inlet port 75 to form a closed loopdecontamination system 85.

Specific size, dimension, and functionality of decontamination chamber77 will vary according to the decontamination needs. The chamber may bescaled down for small articles or scaled up for very large articles andmay be made collapsible for portability needs. According to someembodiments, and with reference to the exemplified embodiment of FIG. 3,the chamber comprises an inner containment structure 87 and an outer“skin” 89 and has an air space 91 between the inner containmentstructure 87 and outer skin 89. The inner structure 87 and outer skin 89are fabricated from a fire and blast retardant material and may includean anti-static coating on surfaces contemplated as being operationallycontacted with ClO₂ fumigant or ClO₂, waste air. In other specificembodiments all piping and tubing of the system through which ClO₂traverses comprise a static-resistant material. Further, thedecontamination system is grounded and utilizes DC current/batteries toavoid realizing an ignition risk associated with ClO₂ gas.

In some embodiments, the decontamination chamber further comprises atleast one air blower 93 positioned in the air space 91, wherein the atleast one blower 93 is sealed and operates on direct current. A blower93 may be positioned in proximity to each door 95 located in the chamber77. In very specific embodiments the decontamination chamber isconstructed to be erected and collapsed by the use of ambient air. Inparticular air may be pumped into support tubes arranged along theperiphery, the tubes become rigid and pull the fabric of the chamber asthey expand, thus erecting the chamber.

The inventive decontamination system is particularly suitable fordecontamination of a building or contained area within a building viathe ductwork of the HVAC system 97, which also serves to decontaminatethe HVAC system. Residual contamination present in HVAC duct work isresponsible for recontamination of decontaminated buildings where thedecontamination methods fail to account for it. In this application, thedecontamination system is configured as an open-loop system withactivating areas (referred to as activators) connected to neutralizingareas (referred to as neutralizers) by connections to the building'sHVAC system 97 comprising an HVAC unit 99 and HVAC duct work 100. Atleast one activating area 3 is in fluid communication with aneutralizing area 7 via the HVAC duct work. Referring to an embodimentillustrated by FIG. 4, multiple independently housed activating areas 3are located in the building relative to the HVAC unit 99 such thatgravity aids in distribution of ClO₂ fumigant through the duct work 100.The number of activators should correspond to the size of the buildingand the number of rooms into which the floor or building is divided, aswell as the desired target concentration of ClO₂. The optimization of aparticular configuration of the system will be readily apparent to oneof skill in the art.

A series of sensors and read-outs may be utilized to monitor the ClO₂concentration throughout the decontamination and neutralizing cycles.Where a decontamination chamber is utilized, concentration of ClO₂fumigant in the decontamination chamber 77 is monitored by a monitoringdevice 101. The device comprises at least one ClO₂ sensor 102, which maybe located in an interior space 103 of the decontamination chamber 77 orexternal to a sampling port 79 in communication with the interior space103 of the decontamination chamber 77. ClO₂ fumigant leakage may bemonitored by one or more monitoring devices comprising ClO₂ sensors 102located in a space exterior 78 to the decontamination chamber 77 orexterior to any of the modular components according to particularembodiments of the invention. Suitable sensors and monitors are wellknown in the art and available from multiple manufacturers.

Embodiments of the invention also include methods based on utilizing theinventive system technology, either as individual components or in anymodular configuration of components. Methods for generating chlorinedioxide fumigant in a directed flow with a minimum of water compriseproviding an activation cup according to embodiments of the inventionand directing an air flow through the cup. According to specificembodiments, the cup comprises an outer layer 15 of crush-resistantthermally bondable non-woven fibers molded into a transversely bisectedaerodynamically-shaped shell 17 where the shell 17 is open at the top 19and has an interior surface 21 and an exterior surface 23. The exteriorsurface 23 and interior surface 21 may include a pattern of corrugations37 to create turbulence in the air flow such that the reaction mechanicsare enhanced to increased production of fumigant. The cup comprises atleast one filter layer 25 including one filter layer adjacent andadherent to an inner surface 16 of the outer layer 15. The filter layermay comprise multiple layers, however at least one layer 25 compriseshigh-loft electret charged fluorine-coated polyolefin microfibers suchthat the activation cup 13 is adapted to retain water and reactionby-products while permitting gas to pass through, directed by the airflow. In specific embodiments, the cup is flexibly suspending in the airflow. Dry reagents for production of ClO₂ fumigant are added to the cup13 and the directed air flow is initiated. Corrugation patterns in thecup create mild turbulence in the flow resulting in a slight vibrationof the cup. “Corrugation” herein is meant to include any surface featurethat disrupts air flow. It is an important consideration to keep the airflow speed low during this process to avoid degrading ClO₂, which is arelatively fragile molecule. The addition of water to the cup initiatesgeneration of ClO₂ fumigant that is directed out of the cup 13 with theair flow while water and ClO₂ generation reaction by-products aresubstantially retained in the cup 13. Analysis of the resultant ClO₂fumigant flow reveal that it is comprised almost entirely of ClO₂fumigant without a significant presence of water or acid vapor.

Although the activation cup aspect is described herein in relation togeneration of ClO₂ fumigant, it is contemplated that the cup wouldprovide similar benefits with respect to the in situ generation of anychemical gas.

Embodiments of the invention further include methods for neutralizingfumigant chlorine dioxide (ClO₂) in a sealed neutralizing area 7. Theneutralizing area 7 comprises a leak abatement space 39 and aneutralizing space 41, and the neutralizing space 41 comprises a seriesof treatment stations and at least one blower. Methods may include theliquid neutralizing solution reservoir treatment station in combinationwith at least one additional treatment station described herein. Apreferred embodiment includes the UV, neutralizing solution,humidification filter, and zeolite treatment stations in sequentialorder. In some embodiments the method comprises blowing ClO₂ fumigantto-be-neutralized into a treatment station comprising ultraviolet light,resulting in partially neutralized air. The blowing is effectuated at aspeed high enough to degrade ClO₂. The air flow is directed to hit acompartment wall of the UV station at an oblique angle in order tocreate disruptions in the air flow as it enters the liquid neutralizingsolution reservoir. The partially neutralized air from the UV treatmentstation by be blown through a diffusion plate and into a treatmentstation comprising a liquid neutralizing solution reservoir.

The reservoir may be divided into chambers separated by diffusion mediain the form of plates or baffles, resulting in bubbling and frothing inthe reservoir and enhanced neutralization reaction mechanics anddegradation, resulting in substantially neutralized air. In a preferredembodiment the liquid neutralizing solution comprises sodium thiosulfateand water. In specific embodiments bubbled solution is captured andreturned to the reservoir by a treatment station comprising ahumidification filter that permits the substantially neutralized air topass through the filter. In further specific embodiments thesubstantially neutralized air then passes and into a treatment areacomprising coated zeolite (coated with one or more of sodium thiosulfateand calcium hydroxide) to neutralize any remaining ClO₂ and to removeother toxic gaseous by-products remaining in the substantiallyneutralized air, resulting in neutralized air; and, (e) optionally,passing the neutralized air through activated carbon to remove odiferousmolecules which may be present in the neutralized air. The activatedcarbon may be in particle form intermixed with the zeolite, or sprinkledover the top of the zeolite layer, or may form a distinct layer throughwhich the neutralized air passes.

The neutralized air is then pulled into the leak abatement space by ablower acting as a pull blower, where it may be circulated in the leakabatement space and recirculated through the neutralizer by a variablespeed blower directing air from the leak abatement space into theneutralizing space and through another UV treatment station. A valvecontrols whether or not re-circulation is effectuated. Leaks detected onthe outside of the sealed housing by sensors/monitors may be vacuumedinto the leak abatement space by one or more hosese sealingly connectingthe leak abatement space to an environment exterior to the housing. There-circulation loop is opened and contaminated air is pulled through bythe variable speed blower directing it into the UV treatment center andinto the reservoir as described earlier.

The decontamination system of the present invention may be configuredinto a specific embodiment having utility for sterilization andtransportation of sterilized product in a single chamber. In thisembodiment the “decontamination chamber” is the transported chamber anda closed loop is formed with a combined activator/neutralizer unit asdescribed herein. An article in need of decontamination is placed intothe decontamination chamber and the method comprises generating ClO₂fumigant and directing the generated ClO₂ fumigant through the closedloop to achieve a concentration of ClO₂ fumigant in the decontaminationchamber across a time frame sufficient to achieve target sterilizationof the product. The concentration may be monitored and affirmed by atleast one ClO₂ concentration sensor. Once the target concentration isreached and held for the target residential time, the decontaminationchamber is decoupled from the sealed housing while maintaining sealingof the decontamination chamber from the environment. The sterilizedarticle is then transported to a target destination in the chamber. Itis contemplated that the decontamination chamber in specific aspects ofthis embodiment may be adapted suitcases, trunks, coolers, medicalcontainment cabinets, and the like.

With reference to FIG. 5, a specific application illustrating use of adecontamination system according to certain embodiments of the inventionto provide and maintain a sterile operating room environment isdescribed. ClO₂ gas is theoretically an ideal sterilant for thisenvironment, which contains a wide variety of substrates. A safe andeffective system for providing a target concentration to an operatingarea of an operating room has heretofore not been developed.

ClO₂ gas is activated in a system activator as described above. Withreference to FIG. 5A, the system comprises a laminar diffuser comprisinga HEPA diffuser is set over the operating table area, and one or moreslotted diffusers set up around the periphery of the operating tablearea. The diffusers are in communication with the room's air supply ductwork connected to the main HVAC system. A temporary plastic wall isinstalled to section off an operating room area just outside thecontemplated air curtain. A conduit from the activator to the air ductsupply is set up so that ClO₂ fumigant may enter an air supply duct ofthe room. A damper in the air supply duct is installed if not alreadypresent, in order to seal off the OR's air supply. An access port to thedecontamination system is installed downstream from the damper. Thedamper is closed. Air from the air supply duct is directed through thelaminar diffuser and the slotted diffusers, forming a ClO₂ air curtainaround the operating area. FIGS. 5B through 5E show how the fumigant isdistributed and dispersed into the OR. When the decontamination needceases, a valve may direct the air from the operating room area to theneutralizer. Re-circulation enhances the neutralization process.

Target concentration may be determined by decontamination needs andregulatory requirements for particular environments. The decontaminationsystem as described herein is capable of reaching and maintainingsterilization conditions for a variety of substrates.

The following Examples are presented to illustrate and clarify certainaspects and embodiments of the invention and should not be construed tolimit the full scope of the invention as defined by the appended claims.

For purposes of the Examples, dry reagents for ClO₂ were provided asMB-10 6 gm tablets (available from Quip Laboratories, Inc. ofWilmington, Del.). Each tablet contains 25-35% by weight inorganic acid,35-45% inorganic salt, 15-24% sodium chlorite, and 5-10% by weightsodium dichloroisocyanurate dihydrate.

Example 1

This example illustrate an embodiment directed to activation of chlorinedioxide in the activation cup and demonstrates that ClO₂ gas is producedand directed through the cup, while water and reaction by-products andsalts remain contained within the activation cup. A well-known problemin the art of ClO₂ decontamination systems is that production of the gasin water from dry reagents involves corrosive salts as a byproduct ofthe reaction. The salts shorten the life of delivery and dispersalequipment. Another well-known problem is the amount of water typicallypresent in the ClO₂ fumigant, since water is necessary to catalyze theClO₂ production reaction. This is particularly problematic wherecorrosion-sensitive articles such as electronic devices are in need oftreatment. Prevention of dispersal of the salts as well as minimizationof water in the treatment air flow is therefore highly desirable.

The filter layer of a specific activation cup embodiment was fabricatedof polymeric microfibers comprise electrat charged fluorinatedmelt-blown polyolefin microfibers having an effective fiber diameter ofabout 0.7 μm. The shell itself was formed by layering the filtermaterial between layers of the crush-resistant thermal molding polymerand press-molding under temperatures sufficient to mold the outer andinner layers; however lower than the melting point of the fiber layer.This is essentially the same technology utilized in the respiratorindustry to fabricate face-worn respiration masks to protect the wearerfrom inhaling particles other than gas molecules, and for trappingexhaled moisture in the apparatus to prevent excessive build-up andinhalation of moisture by the wearer.

Two MB-10 tablets were activated with 30 ml water in the activation cup.The total weight of the cup, water and tablets was 50.6 g. Gas was blownwith a variable air blower through the cup and into a 36 cu. ft.stainless steel tunnel. Electronic equipment was placed in the tunnel.Gas concentration was verified by ATI Porta Sens gas detector throughports in the chamber.

Gas concentration reached 240 ppm and was held for 6 hours. Total weightof activation cup and contents after cessation of reaction was 45.1 gm;hence approximately 5.5 g ClO₂ gas was produced. The activation cup wasdried and inspected. By-product salts were found trapped in the bottomof the activation cup and in the filter later. Neither the fan nor thecomputer equipment showed any effect from the gas.

Example 2

This example illustrates operation of one embodiment of thedecontamination system using recircualtion to aid in the penetration ofthe ClO₂. Demonstration of partial neutralization of ClO₂ withultraviolet light was confirmed.

A roll of moldy filter material having an approximate volume of 7 cu.ft. and exhibiting a moldy odor was placed into a 36 cu. ft. stainlesssteel chamber. The decontamination system cabinet was fitted with aninlet and an outlet port for recirculation. Two MB-10 tablets wereactivated utilizing the activation cup in accordance with Example 1, andgas concentration in the chamber was monitored by an ATI Porta Sensdetector. Two biological indicators were placed about 4 inches insidethe roll on either end and five Rodac plates were used to sample every20 ft. when the material was unrolled. The gas was held for three hoursand reached a maximum concentration of 661 ppm. After thedecontamination period was over, the ClO₂ gas was neutralized with UVlight and gas remaining in the chamber was sampled every 5 min. Thebiological indicators and Rodac plates were sent to Air Filter TestingLabs for verification of results.

The results showed no growth in the biological indicators or the Rodacplates. The moldy smell was no longer perceptible, indicatingsterilization. The UV light dropped the gas concentration about 8 to 14ppm every 5 min., which is relatively slow but effective. Recirculationenhanced the penetrating ability of ClO₂ and the process sterilized theentire roll.

Example 3

This example illustrates an aspect of the system comprising acollapsible decontamination chamber fabricated of fire and blastretardant material with an air layer created between an inner scaffoldand an outer layer. The volume of the chamber was about 300 cu. ft.,which is the volume necessary, for example, to contain a completehospital bed or around ten standard-sized hospital mattresses. Theentire decontamination system was designed to be portable. This examplealso illustrates that recirculation is an effective alternative to 24hour evacuation in off-gassing environments.

An office chair of faux leather, end table, hospital bed, and a roll offilter material were placed in the decontamination chamber in order toprovide data on a range of materials and surfaces. Two biologicalindicators were used, one inside the drawer of the table and the otherplaced about three feet inside the roll of filter material. Two MB-10tablets were activated in the activation cup spaced 70 min. apart inorder to illustrate boosting gas concentration. The gas was recirculatedthrough two openings fitted at the end of the chamber. The test ran forthree hours and an ATI Porta Sens used to monitor gas concentration.

Fumigant gas concentration reached 93 ppm, and then started to drop. Thesecond tablet boosted the concentration to 226 ppm. Biologicalindicators showed negative growth indicating sterilization. When themonitor read zero, the fan was turned off; however the monitor showedthat the ClO₂ gas concentration rose back to 10 ppm after severalminutes. This is the result of absorbent material in the chamberoff-gassing absorbed ClO₂. The fan was restarted and set to high, andthe remaining ClO₂ was evacuated in ten minutes as confirmed bymonitoring.

Example 4

This example illustrates safe control of ClO₂ gas indoors in a confinedspace. The test embodiment of the neutralizing area included aneutralizing solution of sodium thiosulfate along with a finishingfilter composed of zeolite coated with sodium thiosulfate plus carbongranules atop the zeolite layer to trap any residual odors. The wholesystem comprised two loops, one that delivered the gas into the chamberto effectuate decontamination. The second loop was an internal loop thatswept any escaped gas past a UV light back into the neutralizationsolution as a safety feature. The system was contained in a medicalgrade cabinet on wheels for easy portability.

Two MB-10 tablets were used to produce a gas concentration of 72 ppm atthe highest concentration point. Biological indicators were placedinside the collapsible decontamination chamber at the entering andexiting portals. The valves were manipulated and the data demonstratedthat opening the valve a quarter turn on the intake side while openingthe neutralization valve resulted in effective one-pass neutralization.The ATI Porta Sens detector was again used to monitor gas concentration.

The results further demonstrated that during the initial surge some ClO₂gas escaped inside the cabinet but was quickly swept into theneutralizing chamber (within two minutes). Biological indicators showedno growth of microbes. The entire process took about two hours with nogas detected outside the cabinet at any time. Activation fluid insidethe activating cup was neutralized and brought to a safe pH of 7.

Example 5

This example illustrates sterilization of a laboratory incubator in areal-world context. Price Institute for medical research at theUniversity of Louisville reported experiencing molding of tissue samplesby an incubator contaminated with mold spores. Repeated attempts todisinfect the incubator failed.

A decontamination system according to one embodiment of the inventionwas taken on-site to the lab. The incubator measured 2×2×3 ft=12 cu. ft.It was assumed that the internal circulation of the incubating devicehad become infected with mold which could not be reached by conventionalscrubbing. Ambient temperature was 72° F. and ambient humidity was 57%.Temperature of activation was 113° F. A bag attached to thedecontamination system was taped over the door of the incubator with thedoor open. Two biological indicators were placed inside beforehand. OneMB-10 tablet was activated and the generated ClO₂ fumigant was pumpedinto the incubator. The door was closed and taped. The gas was heldovernight, the tape was removed, the bag was placed over the door andthe door was then opened. ClO₂ gas was evacuated and neutralized.Neutralization took about ten minutes. Biological indicators were sentto Air Filter Testing Lab for third party verification of sterilization.

The biological indicators provided positive verification ofsterilization and follow-up reports from the lab indicate that theformally chronic and intransigent contamination problem has resolved.

Example 7

This example, when taken with Example 6, illustrates scalability of thedecontamination system. The Price Institute at University of Louisvillereported a black mold growing in a walk-in cooler in lab 330. The coolerhad a distinct moldy odor and contained several boxes and other items.It was requested that the mold be removed so that new tissue samples andsensitive research items could be safely stored without threat ofcontamination.

Three biological indicators were placed inside the cooler. One wasplaced at the top near the internal blower, one at the bottom near thefloor, the other between boxes on one of the shelves. The cooler'sblower was turned off and plastic sheeting was taped over the dooropening. An entering hole and exiting hole were cut and the hose thatdelivered the ClO₂ gas was inserted and sealed with tape. A total of 6MB-10 tablets were used two at a time until the gas concentrationreached sterilization levels. The process lasted about two hours. Theinternal blower was turned back on just before we began neutralizationof the gas.

The results demonstrated complete efficacy with respect to sterilizationand the gas was neutralized with no leakage. The ability of theinventive decontamination system to remove black mold in a confinedspace without evacuation of the facility is a significant improvementover systems known in the art.

Example 8

This Example illustrates decontamination of a 363 cu. ft. HVAC/ductspace and the flexibility in implementing the modular/portable systemfor effective decontamination of multiple-story buildings. FIG. 4illustrates a basic schematic of the design. Application of embodimentscomprising multiple portable independent activation areas contained in,for example, rolling or easily transportable cabinets, is contemplatedfor convenient decontamination/sterilization of hospital rooms. It iscritical to clean air ducts coming into the room or once air is resumed,the room may become re-contaminated. A very specific application of thisembodiment relates to sterilization of operating rooms as illustratedschematically in FIG. 5.

HVAC ducts often have 90 degree turns and multiple pathways, which poseschallenges for air flow being pushed from a central area into allreaches of the system. For example, multiple story homes may bedifficult to air-condition with a single down-stairs unit. In order toavoid this, and to exploit that fact that ClO₂ is heavier than many airmolecules, a particular configuration of a modular/portabledecontamination system was designed. The test house from Example 6 wasused. All ducts and 34 of the register vents around the house weresealed. An activating unit was placed in each of six rooms on the upperfloor. Each unit had its own variable speed blower, activating cup, andthree-conduit system for reagents, water and neutralizing solution asprovided on the main unit. Unsealed vents were fitted with a connectionthat covered the vent but had anti-static tubing going back to theactivating unit. If there was more than one register vent in a room, asecond connection and tubing was installed and run back to the blower onthe activator's intake side. This resulted in providing a mini loopcirculation per room while remaining open to the main trunk of the HVAC.The main decontamination system unit was placed in the basement attachedto the main trunk of the HVAC system making a closed loop which includedthe entire house. One MB-10 tablet was in each activating unit, whilethree tablets were used in the main unit, for a total of 9 tablets. Theblowers were turned on low for ClO₂ activation. Two biologicalindicators were placed in the main HVAC trunk area and the cycle lasted4 hours. At the end of the cycle the valve to the activating cups wasclosed and the neutralizing area was opened. Blowers were adjusted tohigh speed and ClO₂ gas was entirely evacuated in 20 minutes.

The biological indicators indicated that sterilization of the HVACsystem was successfully effectuated.

It is expressly contemplated that each of the various aspects,embodiments, and features thereof described herein may be freelycombined with any or all other aspects, embodiments, and features. Theresulting aspects and embodiments (e.g., products and methods) arewithin the scope of the invention. It should be understood that headingsherein are provided for purposes of convenience and do not imply anylimitation on content included below such heading or the use of suchcontent in combination with content included below other headings.

All articles, books, patent applications, patents, other publicationsmentioned in this application are incorporated herein by reference. Inthe event of a conflict between the specification and any of theincorporated references the specification (including any amendmentsthereto) shall control. Unless otherwise indicated, art-acceptedmeanings of terms and abbreviations are used herein.

In the claims articles such as “a”, “an” and “the” may mean one or morethan one unless indicated to the contrary or otherwise evident from thecontext. Claims or descriptions that include “or” between one or moremembers of a group are considered satisfied if one, more than one, orall of the group members are present in, employed in, or otherwiserelevant to a given product or process unless indicated to the contraryor otherwise evident from the context. The invention includesembodiments in which exactly one member of the group is present in,employed in, or otherwise relevant to a given product or process. It isto be understood that the invention encompasses all variations,combinations, and permutations in which one or more limitations,elements, clauses, descriptive terms, etc., from one or more of thelisted claims is introduced into another claim. For example, any claimthat is dependent on another claim may be modified to include one ormore elements, limitations, clauses, or descriptive terms, found in anyother claim that is dependent on the same base claim. Furthermore, wherethe claims recite a product, it is to be understood that methods ofusing the product according to any of the methods disclosed herein, andmethods of making the product, are included within the scope of theinvention, unless otherwise indicated or unless it would be evident toone of ordinary skill in the art that a contradiction or inconsistencywould arise.

Where elements are presented as lists, it is to be understood that eachsubgroup of the elements is also disclosed, and any element(s) may beremoved from the group. The invention provides all such embodiments.

The terms “approximately” or “about” in reference to a number generallyinclude numbers that fall within ±10%, in some embodiments ±5%, in someembodiments ±1%, in some embodiments ±0.5% of the number unlessotherwise stated or otherwise evident from the context (except wheresuch number would impermissibly exceed 100% of a possible value). Whereranges are given, endpoints are included. Furthermore, it is to beunderstood that unless otherwise indicated or otherwise evident from thecontext and understanding of one of ordinary skill in the art, valuesthat are expressed as ranges may assume any specific value or subrangewithin the stated ranges in different embodiments of the invention, tothe tenth of the unit of the lower limit of the range, unless thecontext clearly dictates otherwise. Any one or more embodiment(s),element(s), feature(s), aspect(s), component(s) etc., of the presentinvention may be explicitly excluded from any one or more of the claims.

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described and exemplified herein. The scopeof the present invention is not intended to be limited to the aboveDescription and Examples, but rather is as set forth in the appendedclaims.

What is claimed:
 1. A decontamination system comprising: a chlorinedioxide (ClO₂) fumigant activating area, optionally, a by-pass flowarea, a neutralizing area; a first variable speed air blower in directfluid communication with the ClO₂ fumigant activating area, the by-passflow area and the neutralizing area; a valve system for dedicating airflow from the blower to one or more of the areas, wherein the activatingarea comprises an activation cup configured to receive reagents for insitu generation of ClO₂ fumigant, said activation cup being permeable toair and substantially impermeable to water and reaction by-products,further wherein the activation cup is suspended in the activation areasuch that air flowing from the first variable speed air blower into theactivation area flows through and around the activation cup such thatgenerated ClO₂ fumigant passes out of the activation cup with the airflow while water and reaction by-products remain in the activation cup.2. The decontamination system according to claim 1, wherein theactivation cup comprises: an outer layer of crush-resistant thermallybondable non-woven fiber molded into a transversely bisectedaerodynamically-shaped shell, said shell open at the top and having aninterior surface and an exterior surface; at least one filter layerincluding one filter layer adjacent and adherent to an inner surface ofthe outer layer; and, an inner layer of crush-resistant fibrous materialadjacent and adherent to the at least one filter layer inner-most filterlayer; wherein the at least one filter layer comprises high-loftelectrically charged polymeric microfibers and exhibits a melting pointgreater than that of the molded layers.
 3. The decontamination systemaccording to claim 2, wherein the polymeric microfibers compriseelectrat charged fluorinated melt-blown polyolefin microfibers having aneffective fiber diameter of between about 0.5 μm and 12 μm, airpermeability of between 80 l/m²/s and 8000 l/m²/s; and air flowresistance of between 1.5 Pa and 100 Pa.
 4. The decontamination systemaccording to claim 2, wherein the aerodynamic shape of the shellcomprises a substantially triangular shape, a teardrop shape, a pearshape, or a saddle shape.
 5. The decontamination system according toclaim 2, wherein the exterior surface or both the exterior surface andinterior surface of the shell comprises a pattern of corrugationseffective to create turbulence in the airflow around and through the cupresulting in vibration of the cup and accelerated activation of ClO₂fumigant.
 6. The decontamination system according to claim 1, whereinthe activation area comprises a first conduit adapted for controlledmetered addition of water to the activation cup, a second conduitadapted for addition of dry reagents to the activation cup, and a thirdconduit adapted for addition of neutralizing reagents to the activationcup.
 7. The decontamination system according to claim 6, wherein theconduits comprise ball-valves which may be opened and closed by turningwithout manual touching.
 8. The decontamination system according toclaim 1, wherein the by-pass area comprises at least one conduit foraddition of neutralizing reagents directly to the air flow.
 9. Thedecontamination system according to claim 1 wherein the neutralizingarea comprises a leak abatement space and a ClO₂ fumigant neutralizationspace, said ClO₂ fumigant neutralization space comprising: (a) a firsttreatment station comprising ultraviolet light (UV), the first treatmentstation being in operational communication with a variable air blower,wherein the blower may be the first variable air blower or an additionalvariable air blower, said variable air blower set to blow fumigant wasteair at a high speed through the first treatment station, “high” beingdefined as sufficient to degrade ClO₂ present in the fumigant waste air,thereby resulting in partially treated air; (b) a second treatmentstation comprising a reservoir of liquid neutralizing solution, saidsecond treatment station divided into at least three chambers, a firstchamber in direct communication with the first treatment station, asecond main chamber adjacent the first chamber, and a third chamberlocated on the opposite side of the second chamber than the firstchamber, said first, second and third chambers being separated bydiffusion plates, further where the blower of step (a) is positioned sothat air flow from the first treatment center hits the first chamber atan oblique angle, wherein a combination of “high” flow speed, an obliqueflow force, and forcing of the air through the diffusion plates resultin turbulence in the reservoir and degrading of ClO₂ still present inthe partially treated air, resulting in substantially treated air, (c) athird treatment station comprising a humidification filter positionedover the reservoir, said humidification filter configured to capture,contain and return neutralizing solution to the reservoir whilepermitting substantially treated air to pass through; and (d) a fourthtreatment station comprising coated zeolite.
 10. The decontaminationsystem according to claim 9, wherein the liquid neutralizing solutioncomprises sodium thiosulfate and water.
 11. The decontamination systemaccording to claim 9, wherein the zeolite is coated with sodiumthiosulfate.
 12. The decontamination system according to claim 11,further comprising: (e) activated charcoal suitable for removingodiferous molecules from the treated air, wherein the activated charcoalmay be intermixed with the zeolite, set substantially on top of thezeolite, or may comprise a distinct treatment station from the zeolite.13. The decontamination system according to claim 8, wherein thehumidification filter comprises a humidification pad and humidificationfins, said humidification fins comprising grooves and being alignedabove the reservoir and beneath the humidification pad.
 14. Thedecontamination system according to claim 9, wherein the leak abatementspace comprises: (f) a blower adapted for pulling treated air through anexit port of the neutralizing space and into the leak abatement space;(g) a fifth treatment station comprising a housing comprising UV light;and (h) a second variable air blower set to blow air from the leakabatement space through the fifth treatment station and into thereservoir at a high speed, wherein a second diffusion plate ispositioned at an interface between the fifth treatment center and thereservoir, wherein “high” is defined as sufficient to degrade ClO₂present in the leak abatement space.
 15. The decontamination systemaccording to claim 14, wherein the leak abatement space furthercomprises: (i) one or more hoses connecting the leak abatement space toan environment external to the sealed housing, including at least onehose connected to the variable speed blower to provide a vacuum forceeffective to pull potentially contaminated air from the externalenvironment and direct it into the fifth treatment station.
 16. Thedecontamination system according to claim 14, wherein all air blowersare sealed and configured to operate on direct-current power.
 17. Thedecontamination system according to claim 1, wherein the activating areaand neutralizing area may be housed together in one sealed housing orhoused separately in independent sealed housings.
 18. Thedecontamination system according to claim 17, comprising multipleindependently housed activating areas and at least one neutralizingarea.
 19. The decontamination system according to claim 17, wherein theactivation area and neutralizing area are housed together in one sealedhousing, said sealed housing comprising a ClO₂ fumigant outlet port anda ClO₂ waste air inlet port, the decontamination system furthercomprising: a decontamination chamber configured to hold a product to bedecontaminated and comprising an inlet port sealingly connected by apositive flow line to the ClO₂ fumigant outlet port and an outlet portsealingly connected by a negative flow line to the ClO₂ waste air inletport to form a closed loop decontamination system.
 20. Thedecontamination system according to claim 19, wherein thedecontamination chamber comprises an inner containment structure and anouter skin and having an air space between the inner containmentstructure and outer skin, said inner structure and outer skin fabricatedfrom a fire and blast retardant material and having an anti-staticcoating on surfaces operationally contacted with ClO₂ fumigant or ClO₂waste air.
 21. The decontamination system according to claim 20, whereinthe decontamination chamber further comprises at least one air blowerpositioned in the air space, wherein the at least one blower is sealedand adapted to operate on direct current, further wherein at least oneair blower is positioned in proximity to each door located in thechamber.
 22. The decontamination system according to claim 18, whereinthe decontamination system is portable.
 23. The decontamination systemaccording to claim 18 adapted to decontaminate an HVAC system andconfigured as an open-loop system, said HVAC system comprising an HVACunit and HVAC duct work, wherein an activating area housing is in fluidcommunication with a neutralizing area housing via the HVAC duct work.24. The decontamination system according to claim 23, wherein multipleindependently housed activating areas are located relative to the HVACunit such that gravity aids in distribution of ClO₂ fumigant through theduct work.
 25. The decontamination system according to claim 21, whereina concentration of ClO₂ fumigant in the decontamination chamber ismonitored by a monitoring device, said device comprising at least oneClO₂ sensor, wherein the at least one sensor may be located in aninterior space of the decontamination chamber or external to a samplingport in communication with an interior space of the decontaminationchamber; further wherein ClO₂ fumigant leakage is monitored by one ormore monitoring devices comprising ClO₂ sensors located in a spaceexterior to the decontamination chamber.
 26. A method for generatingchlorine dioxide fumigant in a directed flow with a minimum of water,the method comprising: (a) providing an activation cup comprising: anouter layer of crush-resistant thermally bondable non-woven fibersmolded into a transversely bisected aerodynamically-shaped shell, saidshell open at the top and having an interior surface and an exteriorsurface, said exterior surface and interior surface comprising a patternof corrugations; at least one filter layer including one filter layeradjacent and adherent to an inner surface of the outer layer, wherein atleast one filter layer comprises high-loft electret chargedfluorine-coated polyolefin microfibers, wherein the activation cup isadapted to retain water and reaction by-products while permitting gas topass through; (b) flexibly suspending the activation cup; (c) adding dryreagents for production of ClO₂ fumigant to the cup; (d) directing anair flow toward the cup at a low speed such that the corrugations createturbulence resulting in vibration of the cup and acceleration of ClO₂generation, “low” being defined as insufficient to degrade ClO₂; (e)adding water to the cup; thereby initiating generation of ClO₂ fumigantthat is directed out of the cup with the air flow while water and ClO₂reaction by-products are substantially retained in the cup.
 27. A methodfor neutralizing chlorine dioxide (ClO₂) fumigant in a sealedneutralizing area, said neutralizing area comprising a leak abatementspace and a neutralizing space, said neutralizing space comprising aseries of treatment stations and at least one blower, the methodcomprising: (a) blowing ClO₂ fumigant to-be-neutralized into a treatmentstation comprising ultraviolet light, resulting in partially neutralizedair, said blowing effectuated at a speed high enough to degrade ClO₂;(b) blowing the partially neutralized air from the UV treatment stationthrough a diffusion plate and into a treatment station comprising aneutralizing solution reservoir, thereby creating bubbling and frothingin the reservoir and resulting in substantially neutralized air; (c)capturing and returning solution to the reservoir with a treatmentstation comprising a humidification filter that permits thesubstantially neutralized air to pass through the filter and into atreatment area comprising coated zeolite; (d) passing the substantiallyneutralized air through the coated zeolite to neutralize any remainingClO₂ and other toxic gaseous by-products remaining, resulting inneutralized air; and, (e) optionally, passing the neutralized airthrough activated carbon to remove odiferous molecules which may bepresent in the neutralized air.
 28. The method according to claim 27,wherein the neutralizing solution comprises sodium thiosulfate andwater, and the coated zeolite comprises a sodium thiosulfate coating.29. The method according to claim 27, wherein the leak abatement spacecomprises at least one blower acting as a pull blower, a variable speedblower directing air from the leak abatement space into the neutralizingspace, a UV treatment station, and at least one hose sealinglyconnecting the leak abatement space to an environment exterior to thehousing, the method further comprising: (f) pull-blowing treated airfrom the neutralizing space into the leak abatement space; (g)pull-blowing air in the environment exterior to the housing into theleak abatement space through the at least one hose; and (h) blowing airfrom the leak abatement space into a UV treatment station and through adiffusion plate into the reservoir of neutralizing solution.
 30. Afumigant method for sterilization and transportation of sterilizedproduct in a single chamber, the method comprising: (a) providing thedecontamination system according to claim 23; (h) placing a product inneed of decontamination into the decontamination chamber; (c) generatingClO₂ fumigant and directing the generated ClO₂ fumigant through theclosed loop to achieve a concentration of ClO₂ fumigant in thedecontamination chamber across a time frame sufficient to achievesterilization of the product, said concentration monitored and affirmedby at least one ClO₂ concentration sensor; (h) de-coupling thedecontamination chamber from the sealed housing while maintainingsealing of the decontamination chamber from the environment; and (i)transporting the sealed chamber comprising sterilized product.
 31. Afumigant activation cup comprising: (a) an outer layer ofcrush-resistant thermally bondable non-woven fiber molded into atransversely bisected aerodynamically-shaped shell, said shell open atthe top and having an interior surface and exterior surface; (b) atleast one filter layer, including one filter layer adherent and adjacentto an inner surface of the outer molded layer; (c) an inner layer ofcrush-resistant fibrous material adjacent and adherent to the at leastone filter layer; wherein the at least one filter layer compriseshigh-loft electrically charged fluorinated polyolefin microfibers andexhibits a higher melting point that the molded layers.
 31. Theactivation cup according to claim 30, wherein the exterior surface orboth the exterior and interior surfaces of the shell comprise a patternof corrugations.
 32. The activation cup according to claim 30, whereinat least one filter layer is electret charged and comprises a melt-blownmicrofiber having an effective fiber diameter of between about 0.5 μmand 12 μm; air permeability of between 80 l/m²/s and 8000 l/m²/s; andair flow resistance of between 1.5 Pa and 100 Pa.
 33. The activation cupaccording to claim 32 wherein the melt-blown microfiber has an effectivefiber diameter of between about 0.7 μm and 8 μm.